A novel hollow porous structure designed for Na0.44Mn2/3Co1/6Ni1/6O2 cathode material of sodium-ion batteries

Among many promising cathode materials for SIBs, the transition metal oxides have attracted especially extensive attention for uncostly and environmental-friendly. In this paper, the Na0.44Mn2/3Co1/6Ni1/6O2 tunnel cathode material with a hollow porous spherical structure is successfully prepared. Short distance for Na+ diffusion leads to good Na+ diffusion kinetics, so it has excellent rate performance, with the specific discharge capacity of 133 mAh g(-1), 127 mAh g(-1), 116 mAh g(-1), 95 mAh g(-1), and 72 mAh g(-1) at charge and discharge rates of 0.1 C, 0.2 C, 0.5 C, 1 C, and 2 C (1 C = 120 mA g(-1)), respectively. The unique hollow porous structure ensures its excellent cycle stability. Therefore, designing a hollow and porous three-dimensional spherical structure is an effective method. Furthermore, it provides a reliable way for the modification of the cathode material for SIBs in the future.